How to transfer your property tax base to a new home in California

Last updated 2026-07-09

What is a property tax base transfer in California?

A base year value transfer lets you carry your old home's low assessed value to a new home instead of getting reassessed at the purchase price. That one move can save thousands of dollars a year, every year, for as long as you own the new place.

California property taxes are calculated on your assessed value, not your market value. Under Proposition 13 (1978), your assessed value grows by no more than 2% per year once you own a home. Sell and buy a new place, and the new home normally gets reassessed at its full purchase price. In most California markets, that means a brutal tax jump.

The transfer stops that jump. If your current home is assessed at $300,000 but you sell it for $900,000 and buy a new $950,000 home, your tax bill on the new place is based on something much closer to $300,000 than $950,000.

The gap is huge. At California's roughly 1.1% effective property tax rate, a $650,000 difference in assessed value is about $7,150 less in tax a year ^[1]. That is not a one-time refund. It repeats for every year you hold the home.

How did Proposition 19 change the base transfer rules?

Proposition 19 replaced the old base transfer rules with looser ones: you can now buy anywhere in the state, buy a more expensive home, and transfer your base up to three times if you qualify by age. Voters approved it in November 2020 and it took effect April 1, 2021 ^[3].

For most of California's history, base year value transfers ran under Propositions 60 and 90, passed in 1986 and 1988. Those rules were tight. You had to be 55 or older, you could only do it once, the replacement home had to be equal or lesser value than the home you sold, and only a handful of counties accepted transfers from other counties.

Here is what Prop 19 changed:

• Age requirement: Still 55 or older. Same as before.
• How many times: Up to three transfers in your lifetime if you're 55+. Before Prop 19, it was once.
• County restrictions: Gone. You can buy anywhere in California. Under the old Prop 60/90 rules, intercounty transfers only worked in counties that had adopted an ordinance allowing them, and participation was limited ^[2].
• Value cap: Under old rules, the replacement had to be equal or lesser value. Under Prop 19, you can buy a pricier home, but your base rises by the difference between the new home's purchase price and your old home's sale price.

Prop 60 and 90 claims are no longer accepted for purchases made after April 1, 2021. If you bought before that date and qualify under the old rules, some counties may still take a Prop 60/90 claim depending on their cutoff ^[3].

One part of Prop 19 gets buried in the good-news coverage. It sharply narrowed the parent-child and grandparent-grandchild exclusion from reassessment. That's a separate topic. But if you're thinking about inheriting or gifting property, know that the rules tightened hard.

Who qualifies for the base year value transfer?

Three groups qualify under California Revenue and Taxation Code Section 69.5, as amended by Prop 19: homeowners 55 or older, severely and permanently disabled homeowners, and victims of a wildfire or Governor-declared disaster.

Category 1: Age 55 or older. At least one owner of the original property must be 55 or older on the date the original property sells. If a married couple owns the home, only one spouse has to meet the age requirement.

Category 2: Severely and permanently disabled. You must be unable to engage in any substantial gainful activity because of a medically determinable physical or mental impairment that has lasted or is expected to last at least 12 continuous months or result in death. The California State Board of Equalization (BOE) says this standard tracks the Social Security definition of disability ^[4].

Category 3: Victims of wildfire or Governor-declared disaster. The original property must have been substantially damaged or destroyed in a wildfire or other disaster declared by the Governor. No age requirement applies here. Revenue and Taxation Code Section 69 governs this provision ^[10].

What counts as an original property? It has to be your principal residence, the place you actually lived as your primary home. Vacation houses and rentals don't qualify as the property you transfer from. The replacement home also has to become your new principal residence ^[5].

People miss this: if you owned the original home jointly and only one owner qualifies by age or disability, you can still transfer the base. The transfer applies to that person's ownership interest.

How is the new assessed value calculated when you transfer the base?

If the replacement home costs the same or less than your old home's sale price, you get a full transfer and your new assessed value equals your old one. If it costs more, your new assessed value equals your old assessed value plus the difference between the new purchase price and the old sale price.

The formula trips up almost everyone the first time. So let's run real numbers.

If the replacement home costs the same or less (equal or lesser value): Full transfer. Your new assessed value equals your old home's assessed value at the time of sale. Done.

If the replacement home costs more: New Assessed Value = Old Assessed Value + (Replacement Purchase Price - Original Sale Price)

Example:

• Old home assessed value: $250,000
• Old home sale price: $800,000
• New home purchase price: $1,000,000
• Difference: $1,000,000 - $800,000 = $200,000
• New assessed value: $250,000 + $200,000 = $450,000

Without the transfer, you'd pay tax on $1,000,000. With it, you pay on $450,000. At a 1.1% effective rate, that's about $6,050 a year in savings ^[1].

The California BOE publishes a worksheet for this in its Prop 19 guidance ^[4]. Run your own numbers before you assume the transfer is worth it. If your replacement home is far more expensive than what you sold, the savings shrink.

Scenario	Without Transfer	With Transfer	Annual Savings (at ~1.1%)
Buy equal-value home	Tax on $1,000,000	Tax on $250,000	~$8,250
Buy 25% more expensive home	Tax on $1,250,000	Tax on $700,000	~$6,050
Buy 50% more expensive home	Tax on $1,500,000	Tax on $1,000,000	~$5,500
Buy cheaper home	Tax on $700,000	Tax on $250,000	~$4,950

*Old assessed value assumed at $250,000; old sale price assumed at $1,000,000 for the more-expensive scenarios. Figures are illustrative, based on California's approximate effective rate ^[1].*

What is the filing deadline to claim a base year value transfer?

You have three years from the purchase date of the replacement property to file your claim with the county assessor ^[5]. This is a firm deadline. Miss it and the assessor will not grant the transfer retroactively.

One wrinkle: you can file the claim before you even sell the original property, as long as you have escrow open on the replacement. But you eventually have to prove the original home sold and that you lived in it as your primary residence.

Some counties let you file at the time of purchase, which is the smartest move. Ask the county assessor's office for its intake process. Los Angeles County, for example, uses BOE-19-B and handles a heavy volume of these claims given the region's turnover among older homeowners ^[9]. If you're dealing with LA County specifics, our guide on Los Angeles County property tax covers the local assessor's process in more detail.

In Santa Clara County, where prices rank among the highest in the state, the savings can be large. The Santa Clara property tax article has the local filing procedures.

Key dates to remember:

• Prop 19 applies to purchases on or after April 1, 2021 ^[3]
• Three-year filing window from the replacement property purchase date ^[5]
• You must establish principal residence within the required timeframe ^[5]
• If you qualify under old Prop 60/90 rules and bought before April 1, 2021, contact your county now; those windows may have closed

How do you actually file the claim? What forms do you need?

You file at the county level, not with the state, and you file with the assessor in the county where your new home sits, not the county you're leaving. The BOE has standardized the forms, and you download them free.

• BOE-19-B: Claim for Transfer of Base Year Value to Replacement Primary Residence for Persons at Least Age 55 Years ^[4]
• BOE-19-C: Claim for Transfer of Base Year Value to Replacement Primary Residence for Severely and Permanently Disabled Persons
• BOE-19-D: Claim for Transfer of Base Year Value to Replacement Primary Residence Acquired by a Person Who is Eligible as Certified by a Physician
• BOE-19-V: Claim for Transfer of Base Year Value to Replacement Primary Residence Damaged in a Governor-Declared Disaster

All four come from the California BOE website ^[4].

What you submit with the form:

• Proof of age (driver's license, passport, birth certificate)
• Proof the original property was your principal residence (usually two years of tax returns showing that address, or utility bills)
• Closing disclosure or settlement statement from the sale of the original home
• Closing disclosure from the purchase of the replacement home
• A completed, signed claim form

Disability claims also need a physician's certification or a Social Security Administration disability determination.

After you submit, the assessor reviews the claim. Processing runs anywhere from a few weeks to several months by county. If the assessor already assessed your new home at full purchase price before processing your claim, you should get a refund of the overpaid taxes back to the purchase date, more than the date your claim was approved.

Can you transfer the base if you buy before you sell?

Yes. Prop 19 lets you buy the replacement home either before or after you sell the original. The only hard rule is that both transactions happen within two years of each other ^[5].

Found your dream house first and bought it before selling your old home? You're still eligible. You file the claim, the assessor processes it provisionally, and once the original property sells you hand over the final documentation.

This is common for older homeowners who don't want to be caught homeless in a hot market. Buy first, move in, then sell. The two-year window is tight enough to watch closely. If the old home lingers on the market and doesn't sell within 24 months of the replacement purchase, you lose eligibility.

Buy first? File the BOE form as soon as escrow closes on the new home. Don't sit on it. The three-year clock starts on the purchase date, and waiting to file until after the old home sells only adds risk if that sale gets delayed or falls apart.

Are there situations where the transfer won't save you money?

Yes, and almost nobody warns you about them. If your old home's assessed value already sits near its market value, there's little base to protect, and the transfer barely helps.

Homeowners who bought recently, say within the last five to eight years, in a flat market often find the Prop 13 cap hasn't opened much of a gap between assessed value and current market value. Not much base means not much savings.

Move to a much pricier home and the upward adjustment to your base eats into the savings. Run the formula before you close. The BOE worksheet handles this ^[4].

Timing matters too. Move to a county loaded with bond measures, special assessments, or Mello-Roos taxes, and your total bill can climb even with a favorable base transfer. The base transfer only touches the 1% general levy portion. Parcel taxes, school bonds, and special district fees don't track assessed value and don't carry over.

One more thing. The transfer only applies to a purchased replacement home. Renting a place preserves nothing for a future purchase.

What happens if the county assessor denies your claim?

If the assessor denies your base year value transfer claim, you can appeal to the county Assessment Appeals Board (AAB). The filing window runs about 60 days from the denial, though it varies by county, so check yours.

Denials usually come down to a few things: the claim was filed late, the original property didn't qualify as a principal residence, you didn't meet the age or disability requirement at the time of sale, or the replacement wasn't occupied as your primary residence in time.

Make your appeal answer the exact reason for the denial. A documentation problem (wrong form of ID, missing closing disclosure) is easy to fix. If the assessor claims the original home wasn't your principal residence, bring evidence: income tax returns with that address, voter registration, utility bills, DMV records.

Maybe the assessor granted the claim but calculated the new assessed value wrong. Same 60-day (or county-specific) window applies to challenge the value at the AAB. Keep copies of everything you submitted.

Dealing with a Los Angeles County denial? The la-county-property-tax guide walks through the AAB filing process for LA specifically.

How does the base transfer interact with other California property tax exemptions?

The base year value transfer and the Homeowners' Exemption are separate benefits, and you should claim both. One sets what your property is assessed at. The other shaves $7,000 off that figure.

The Homeowners' Exemption cuts assessed value by $7,000, which saves roughly $70 to $100 a year depending on your local rate ^[6]. It renews automatically in later years once you've filed, but you have to file an initial claim when you move. The county assessor mails a form after you record the deed. Return it fast.

The Disabled Veterans' Exemption is its own benefit with its own income and disability thresholds. It doesn't interact directly with the base transfer.

Got a commercial or investment property and wondering about those bills? The structures work differently. Santa Clara property tax covers commercial assessments in the Bay Area.

Here's the trap. The base transfer does not reset your Supplemental tax liability. When you buy a new home in California, the county issues a Supplemental Assessment for the gap between the prior owner's assessed value and your purchase price. If your base transfer claim is still pending, you might get a Supplemental bill at full purchase price, then a corrected bill and refund once the claim clears. That refund can take months. Budget for it.

What if your situation doesn't fit neatly into the Prop 19 rules?

Trusts, divorces, unmarried co-owners, and the death of a qualifying spouse all come up often enough to answer head-on. Most straightforward cases don't need a hired gun. The messy ones sometimes do.

Trusts: If the property sits in a revocable living trust, California treats the trust as the owner for property tax purposes. The individual beneficiary who is 55+ or disabled can still qualify, as long as they occupied the original property as their principal residence ^[4]. File the claim with documentation tying the trust to the qualifying individual.

Divorcing couples: If one spouse is under 55 and the other is 55+, and the over-55 spouse buys the replacement property, they may still qualify as long as that spouse holds an ownership interest. Talk to the county assessor, and possibly a property tax attorney, before closing if divorce muddies ownership.

Co-owners who aren't married: If two siblings own a home together and one is 55+ and one isn't, the qualifying sibling can claim the transfer for their proportionate interest. The transfer applies to the qualifying person's share, not the full assessed value.

Death of a qualifying spouse before sale: If the qualifying spouse dies before the original property sells, eligibility may be affected. The California BOE has addressed some of these in guidance letters, but this is a case where a property tax consultant or attorney earns their fee.

If your situation is clean, you really don't need to hire anyone. The BOE forms read plainly and county assessors' offices are generally helpful. Want to handle this yourself and also fight any dispute over your new assessed value? A DIY approach like the TaxFightBack appeal kit keeps 100% of the savings in your pocket instead of handing a contingency firm 30 to 50% of what you recover.

Frequently asked questions about California's property tax base transfer

The FAQs below cover the questions readers ask most. Read them even if your situation looks simple. The answers sometimes surface a filing step or deadline people routinely blow.

Frequently asked questions

Can I transfer my property tax base more than once in California?

Yes. Under Proposition 19 (effective April 1, 2021), homeowners 55 or older can transfer their base year value up to three times in their lifetime. Under the older Prop 60/90 rules that applied before April 1, 2021, only one transfer was allowed. If you already used your one transfer under the old rules, you still have up to two more available under Prop 19 for purchases after April 1, 2021.

Do both spouses have to be 55 or older?

No. California Revenue and Taxation Code Section 69.5 requires at least one owner of the original property to be 55 or older on the date of sale. For a married couple, only one spouse needs to meet the age requirement. The qualifying spouse should also appear on the deed of the replacement property, though the county assessor's office can confirm specific titling requirements.

Does the replacement home have to be in the same county as the home I'm selling?

No. Proposition 19 eliminated county restrictions entirely. You can sell a home anywhere in California and transfer your base year value to a replacement home anywhere else in California. Under the old Prop 60/90 rules, intercounty transfers were limited to participating counties. That limitation is gone for purchases on or after April 1, 2021.

What if I buy a more expensive home than the one I sold?

You can still transfer your base, but it won't be a full transfer. Your new assessed value equals your old assessed value plus the difference between the new home's purchase price and your old home's sale price. Example: old assessed value $300,000, old sale price $800,000, new purchase price $1,000,000. New assessed value = $300,000 + ($1,000,000 - $800,000) = $500,000. You still save compared to full reassessment at $1,000,000.

What forms do I use to file a Prop 19 base transfer claim?

Use BOE-19-B for the age-55 transfer, BOE-19-C for severely disabled persons, or BOE-19-V for disaster victims. All forms come from the California State Board of Equalization website at boe.ca.gov. File with the county assessor in the county where your replacement home is located. Bring proof of age or disability, closing disclosures for both properties, and proof of prior principal residence.

How long does the county have to process my claim?

California law doesn't set a maximum processing timeline for base transfer claims. In practice, counties take anywhere from four weeks to six months or more depending on backlog. If the assessor has already placed a full-market-value assessment on your new home while your claim is pending, you should get a corrected assessment and a refund of overpaid taxes back to the original purchase date once the claim clears. Keep all your filing receipts.

Can I transfer my base if the original property was held in a trust?

Generally yes, as long as the qualifying individual (age 55+ or disabled) was the beneficial owner and used the original property as their principal residence. The California BOE has confirmed this in guidance materials. You'll need documentation connecting the trust to the qualifying individual. Some counties may ask for the trust document itself to verify the beneficiary relationship.

Does a base year value transfer affect my Supplemental Assessment?

The transfer affects your base assessed value going forward, but a Supplemental Assessment is issued when you buy the new home, based on the difference between the prior owner's assessed value and your purchase price. If your base transfer claim is pending, you may get a Supplemental bill at full purchase price, then a corrected bill and refund after approval. The refund covers the excess Supplemental tax from the purchase date, more than the approval date.

What if I sold my home and rented temporarily before buying a replacement?

The replacement home must be purchased within two years of the sale of the original property. There's no restriction on what you do between those two events, so renting temporarily is fine. Track your two-year window carefully from your original home's closing date. Exceed two years and you lose eligibility for the transfer entirely, no matter how compelling your circumstances.

Can a disabled person under 55 use the base year value transfer?

Yes. Severely and permanently disabled individuals qualify for the base transfer under Prop 19 regardless of age, using form BOE-19-C. The disability standard tracks the Social Security Administration's definition: a medically determinable physical or mental impairment that prevents substantial gainful activity and has lasted or is expected to last at least 12 months or result in death. A physician's certification or SSA determination letter is typically required.

Can I still claim a Prop 60 or Prop 90 transfer if I bought my home before April 1, 2021?

Possibly. Prop 60/90 claims for purchases before April 1, 2021 may still be accepted by some counties depending on their cutoff dates. Contact the county assessor where your replacement home is located immediately if you think you have an outstanding Prop 60/90 claim. Those deadlines are very close or already passed depending on when you purchased.

What happens if the assessor denies my base transfer claim?

You can appeal the denial to the county Assessment Appeals Board. The filing window is typically 60 days from the date of denial, but check your specific county's rules. Address the exact reason cited in the denial: documentation gaps are fixable, eligibility disputes need evidence. Common winning evidence includes income tax returns, voter registration, utility bills, and DMV records establishing the original property as your principal residence.

Does the base transfer affect Mello-Roos or special assessment taxes?

No. Mello-Roos fees, parcel taxes, school bonds, and special district assessments are not based on your assessed value. They are fixed charges per parcel or per square foot, and the base transfer doesn't change them. Only the 1% general property tax levy portion of your bill is calculated on assessed value. In some communities, these add-ons are large, so research the full tax bill for any replacement home before buying.

Sources

1. California State Board of Equalization, California Property Tax: An Overview (Publication 29): California's effective general property tax rate is approximately 1% of assessed value under Proposition 13, used to calculate illustrative savings figures in this article
2. California State Board of Equalization, Base Year Value Transfers - Propositions 60/90/110: Under Prop 60/90, intercounty transfers were accepted only by counties that adopted an ordinance allowing it; participation was limited and varied over time
3. California State Board of Equalization, Proposition 19 Overview: Proposition 19 took effect April 1, 2021, replacing Propositions 60, 90, and 110 for base year value transfers
4. California State Board of Equalization, Proposition 19 Forms and Instructions (BOE-19-B, BOE-19-C, BOE-19-D, BOE-19-V): Standardized state forms for Prop 19 base year value transfer claims, including eligibility rules and the calculation worksheet for replacement homes of greater value
5. California Revenue and Taxation Code Section 69.5: Establishes the three-year filing deadline from date of replacement property purchase, the two-year window for buy-before-sell scenarios, and the principal residence requirement
6. California State Board of Equalization, Homeowners' Exemption (Publication 108): The Homeowners' Exemption reduces assessed value by $7,000, yielding approximately $70-100 in annual tax savings at prevailing rates
7. California Legislative Analyst's Office, Proposition 19 Fiscal Analysis: LAO analysis of Proposition 19's fiscal effects, including the expansion of base year value transfer eligibility to three lifetime transfers for qualifying homeowners
8. California Secretary of State, Proposition 19 Official Voter Guide (November 2020): Official voter guide text for Proposition 19, describing the ballot measure's eligibility expansions, county transfer changes, and effective dates
9. Los Angeles County Office of the Assessor, Proposition 19 Information: LA County Assessor's guidance on filing BOE-19-B and processing base year value transfer claims for replacement properties in Los Angeles County
10. California Revenue and Taxation Code Section 69 (Disaster Relief Transfers): Authorizes base year value transfers for victims of Governor-declared disasters and wildfires, separate from the age-55 and disability provisions